The power supply is one of the common failure point in a computer. The power supply is inside the computer that converts the 110 volts from the wall to lower voltages to power the internal components like the system board, hard drive and DVD drive. Power supply will fail due to over heating if laptop or PC internal fan stops spinning. They will fail from age though, they can last a very long time. Power supplies are probably even more likely to fail from a power surge than a hard drive is.